Refrigerating apparatus



Nov. 8, 1938. A. PHILIPP 2,135,316

'REFRIGERATING APPARATUS Original Filed April 20, 1935 2 Sbeefs-Sheet 2J INVENTOR. LlYhQE ICL' If PHIL/PP ATTORNEY.

- UNITED STATES/PATENT OFF-ICE aEFmGamrmG APPARATUS j Lawrence A.Philipp, Detroit, Mich., assignor, by

mesne assignments, to Nash-Kelvinator Corporation, Detroit, Mich land acorporation of Mary- Application April 20, 1933, Serial No. 666,944

Renewed January 24, 1935 I 11 Claims.

This invention relates to refrigerating .appa-j ratus and moreparticularl y to the method and apparatus for controlling temperaturesin such apparatus.

.One of the objects of myinvention is to provide a fundamentally new ofrefrigeration wherein a system and method simple compact unit isutilized for freezing ice cubes and the like and for cooling circulatingair in 'a refrigerator cabinet in animproved manner without thecollection of frost on its surfaces exposed to said circulating air atleast part of the time.

Another object of my invention is to provide a refrigerating apparatusof terms for cooling a plurality the type which ineludes primary andsecondary refrigerating sysof zones, and to provide an improvedarrangement for maintaining a temperature differential between saidsystems.

Another object of my invention is to provide a refrigerating apparatusof the type which includes a primary and secondary refrigerating systemfor cooling a plurality of v zones, and to provide an improved met hodfor maintaining a temperature differential between said systems. Anotherobject of my invention consists in an improved method of controllingtemperatures in the primary and secondary said apparatus.

systems of the aforemary refrigerating system inoperative forperiodically defrosting any part of the apparatus.

Another object of my in tion the effective area of vention is toproporthe heatdissipating portion of the secondary-condenser withrespect to the heat absorbing area of the secondary evaporator tomaintain a temperature differential between the heat absorbing medium ofthe condensing zone and the secondary evaporator.

Other objects and advantages will be apparent from the followingdescription, reference being bad to the accompanying drawings.

In the drawings: Fig. 1 is a vertical view in cross section of arefrigerating apparatus embodying features of my invention;

Fig. 2 is a view taken a long the line 22 of Fig. 1, with a portion ofthe enclosure for the cooling apparatus broken away;

Fig. 3 is a view of a modified form of refrigerating apparatus embodyingfeatures of my invention; and g Fig. 4 is a further'modified form ofrefrigerating apparatus embodying features of my invention.

Referring to the drawings, the numeral designates, in general, aninsulated cabinet having a food storage compartment 2|, the inner wallsof which are formed by a metallic liner 22. Preferably, the liningmember-'22 ,is provided'with a coating of vitreous enamel, such asporcelain, toprovide a neat appearance and surface which maybeeasily-cleaned.

Within the confines of the liner 22 there is disposed a' refrigerantevaporating element 25 of a primary refrigerating system 21. The element25 is of the plate type, whichmay be of any suitable construction, andis horizontally disposed in the cabinet slightly spaced from the topwall thereof. The element 25 is arranged for supporting ice makingreceptacles 25 on its upper surface immediately below the top wall ofthe cabinet .20.

In addition tothe primary evaporating element 25, the-primaryrefrigerating'sy'stem 21 includes a compressor 30, motor 32, condenser34, and a high side float mechanism 36. The compressor withdraws gaseousrefrigerant from the element 25 through vapor. return conduit 38,compresses the gaseous refrigerant and delivers it to the condenserwherein it is liquefied and from which it is delivered to the high sidefloat mechanism. Liquid refrigerant is delivered tothe element 25through a liquid supply conduit 40 under the control of float mechanism35..

A secondary refrigerating system is provided for cooling the circulatingair in the. compartment 2| and also for supporting receptacles forfreezing and storing frozen substances in close proximity. to theprimary evaporating element 25 where said substances will, be frozen orretained in frozen condition by the refrigerating effect of the primaryevaporating element 25.

The secondary refrigerating system 42 comprises, in'general, arefrigerant evaporating element 45, the interior of which forms anevaporating region, and a refrigerant-condensing element 46, theinterior of which forms a condensing region. The elements 45' and 46 areconnected together and are in open communication with each other bymeansof conduits 41. The secondary refrigerant evaporating element 45 issubstantially of the same size as the primary refrigerant evaporatingelement 25 and is horizontally disposed within the cabinet directly be-I low the element 25. The secondary evaporating element is arranged forsupporting receptacles 49 on its upper surface and for cooling thecirculating air in the compartment 2| by the circulating air contactingwith the underside of said element. The secondary refrigerant condensingelement 46 is, preferably, rectangular' 7 that the effective area fordissipating heat abfled form of condensing element for the secondarysorbed in the secondary system is considerably less than the heatabsorbing area of the secondary evaporating element 45. As shown in Fig.2, the secondary condensing element 46 is considerably smaller in sizethan the evaporating element 45. .By thus providing a relatively smallcondensing element 46, the surface thereof which contacts with theprimary evaporating element will be such that only a portion of theevaporated refrigerant in the secondary system 42 will be condensed, anda portion thereof is retained in vapor form in the condenser 46 where itapplies a definite pressure upon the liquid refrigerant in the secondaryevaporating element 45, to thus maintain a heat lag between thesecondary evaporating element and the primary evaporating element. Thus,by proportioning the eile'ctive heat dissipating area of the secondarycondensing element and the heat absorbing area of the secondaryevaporating element, 9. definite temperature difierential may bemaintained between the primary and secondary refrigerating systems.

Referring now to Fig. 3, there is shown a modisystem 42. In thismodified form of the invention, the secondary refrigerant condensingelement 52 is provided for condensing evaporated refrigerant in thesecondary system. As will be noted, the condensing element 52 issubstantially the same size as the primary evaporating element 26. In anarrangement of this type. I also proportion the eflective area of theheat dissipating portion of the condensing element 52 with respect tothe heat absorbing area of the secondary evapcrating element. In thisarrangement, however, the effective area of the condenser 52 is limitedby substantially entirely filling the secondary evaporating element andcondensing element with liquid refrigerant so that the upper interiorsur'- face of the condensing element is partly in contact with some ofthe liquid refrigerant in the secondary system, and some of the upperinterior surface of the condensing element is slightly spaced from theliquid refrigerant in the secondary system. Thus, the upper interiorsurface of the condensing element 52 need not be all on the same planebut is slightly undulating so that portions thereof contact with theliquid refrigerant in the secondary system, while other portions thereofare slightly spaced from the liquid refrigerant in the secondary system.This limits the effective area of the condensing element 52.

As shown in Fig. 4, another arrangement for maintaining a temperaturedifferential between the primary refrigerant evaporating element and thesecondary refrigerant evaporating element 53 in the aforesaid apparatusis to merely introduce a slight film of liquid refrigerant 54 into therefrigerant evaporating element so that the amount thereof isinsufficient to at any time cool the surfaces of the secondaryevaporating element to as low a temperature as the quantity of liquidcontained in the primary evaporating element cools the surfaces of theprimary element.

Preferably, the temperature differential which is maintained between theprimary evaporating element 25 and the secondary evaporating element 45is such that the circulating air in the compartment 2| is cooled to thedesired temperatures without collecting frost on the surfaces of theevaporating element 45 at least part of the time during its operation.This may be accomplished by operating the evaporating element 45 attemperatures which would allow the collection of a slight film of frostthereon during the onphase of the refrigerating cycle of the primarysystem 21, and allow the frost to be melted from the element 45 duringthe off-phase of the refrigerating cycle of the system 21. If desired,however, the secondary evaporating element may be operated attemperatures slightly above that which would cause the collection offrost and ice thereon due to the deposit of moisture from thecirculating air in the compartment 2|.

In order to prevent the collection of frost and ice on the primaryevaporating element 25 and the upper surface of the secondaryevaporating element 45, and to provide suitable freezing zones for thesubstances contained in trays 26 and 49,'I have provided a metallicenclosure 60 and a front closure plate 62. The enclosure 60 is providedwith out-turned flanges 64 which are secured to the top wall of thecabinet 2| in any suitable manner, and inturned flanges 66 which aresecured to the top wall of the secondary evaporating element 45 in anysuitable manner. The enclosure 68 forms a suitable enclosure for thesides and rear portion surrounding the primary evaporating element 25,the secondary condensing element and the top wall of the secondaryevapor ating element 45. The front closure plate 62 cooperates with theclosure 60 for so enclosing the primary evaporating element, secondarycondensing element and the top wall of the secondary evaporating elementagainst the circulating air within the compartment 2|. The front closure62 is provided with openings 10 and II to permit the insertion andremoval of the receptacles 26 and 49, respectively. The openings 10 andH are closed by doors 13 and '14, respectively.

In order to increase the heat transfer characteristics of the secondaryevaporating element 45 I have provided a plurality of U-shaped heatabsorbing fins 15. The fins are preferably equally spaced and arrangedin parallel relation across the underside of the element 45. Immediatelybelow the secondary evaporating element 45', I have positioned a pair ofbailies and drip conducting plates 18. The members 18 are arranged fordirecting the fiow of air in the compartment 2|, and also for receivingthe drip water from the secondary evaporating element 45 and conductingit to a drip receptacle 80 supported by shelf 82. i

From the foregoing, it will be noted that I have provided an improvedarrangement and method for maintaining a temperature differentialbetween a primary and secondary refrigerating system which is verysimple to construct and'is so arranged that it consists of no movingparts whatsoever or any parts in the secondary porization reductionof'the amount of association between ondary system.

evaporating element 45. It

1 frost and ice upon system which would be'likely to become faulty inoperation to vary the temperature differential maintained between it andthe primary system.

I have provided an automatic thermostatically controlled switch 85, towhich is conmeted a thermostatic fluid containing bulb 81,

whichcontrols the operation of the switch 85 in the well known manner.The'iluld containing thermostatic bulb 81 is placed in contact with asecondary evaporating element 45, to thus control the operation of theprimary systemin response to changes in temperatures in the element 45.The switch 85 opens and closes the motor circuit to the power mains 90in response to changes in temperatures in element 45.

Thus, it will be noted thatrpredetermined temperatures may be maintainedwithin the evaporating element 45, by controllingthe operation of theprimary refrigerating system in response to changes in temperatures inthe secondary will also be noted that the relative temperatures existingin the secondary evaporating element 45 and the primary evaporatingelement 25 may be determined in various manners. In the embodimentsofthe invention disclosed, .the heat lag between the evaporating regionand the condensing region is increased by reducing the amount ofassociation betweenmolecules of evaporated refrigerant and thecondensing portion. This can be accomplished by limiting the effectivearea of the secondary condensing element relative to the eifec tive areaof the secondary evaporator, in which case an increased pressure ispresent in the secondary system which in effect reducesthe vain thesecondary evaporator, or, this molecules of evaporated refrigerant andthe condensing portion can be accomplished by utilizing,

a small amount of refrigerant in the seconly By these arrangements, icecubes and the like may temperature for the preservation of foods storedin the compartment 2| without the collection of its exposed surfaces, orwith the collection of a slight film of frost thereon during theon-phase of the refrigerating .cycle of the primary system which ismelted during the off-phase of the refrigerating cycle of the -primaryrefrigerating system. It will also be noted that by the arrangement ofparts in the cabinet, the same element which cools the circulating airwithin the cabinet provides a support for receptacles containingsubstances to be frozen or to be retained. in a frozen condition by therefrigerating effect of a heat absorbing element which is provided forthe rapid freezing of substances.

Although only a preferedforrn of the invention has been illustrated, andthat form described be apparent to those skilled in invention or fromclaims.

What I claim as my invention is:

the scope of the appended 1. The process of refrigeration which consistsin establishing refrigerant condensing andevaporating zones in' opencommunication with each other, maintaining .said zones substantially en-In order to con-,

be rapidly frozen by the re-.

. to the first named cooling frigerating effect of the'primaryevaporating eleelement whereby the peratures above the freezing point ofwater, said second shelf having an air cooling portion and beingprovided with a surface for supportingfrozen'substances immediatelybelow the first named shelf to thereby maintain said substances in afrozen condition by the refrigerating effect of the first named shelf.

3. Refrigerating apparatus comprisin in combination, a cooling elementfor freezing substances, a second cooling element having a portionlocated directly below the first element, and means for operating thesecond element at least part of the time at temperatures above thefreezing point of water, said second element having an air coolingportion and being provided with a surface for supporting frozensubstances immediately below the first named element to thereby maintainsaid substances in a frozen condition by the refrigerating effect of thefirst named element.

4. Refrigerating apparatus combination, a cabinet having a food storagecompartment, a cooling element disposed in said cabinet-for freezingsubstances, a second cooling element disposed in said cabinet forcooling the circulating air in operating the first named cooling elementat temperatures sufficiently low enough to cause comprising, in

rapid freezing of 'saidsubstanceaand means for operating said secondnamed element; at temperatures above that which would permit operationwithout collecting frost and ice thereon at least part of the time, andsaid second named cooling element being so positioned with respectelement that frozen substances may be supported thereon to be retainedin a frozen condition by the refrigerating eflect of the first namedcooling element.

5. Refrigerating apparatus comprising, in combination, a cabinet, a pairof vertically spaced plate type evaporating elements disposed in saidcabinet and being adapted to support ice making receptacles one abovethe other, means enclosing the upper element and the uppermost part ofthe lower element from the circulating air in the cabinet, and means foroperating the lower element at a higher temperature than the upperunderside of the lower element may cool the circulating air in saidcabinet without collecting frost thereon at least part of the tim andtheupper surface thereof may be used for supporting one of said ice makingreceptacles for freezing the contents thereof by the refrigeratingeffect of the upper element.

6. Refrigerating apparatus comprising, in combination, a cabinet, a pairof vertically spaced element whereby the underside of the lower elementmay cool the circulating air in said cabinet from the. circulating 'airin for operating the lower ele- 3 ment at a higher temperature than theupper said compartment, means for e without collecting frost thereon atleast part of the time, and the surface thereabove providing a supportfor one of said ice making receptacles for freezing the contents thereofby the refrigcrating effect of the upper element, and means responsiveto changes in temperatures of the lower element for controlling therefrigerating effect of the upper element.

'7. Refrigerating apparatus comprising, in combination, a cabinet havinga food storage compartment, a primary refrigerating system including arefrigerant evaporating element disposed in said cabinet outside ofdirect contact with the circulating air in said compartment, a secondaryrefrigerating system including a refrigerant evaporating elementdisposed in the path of circulating air in the food compartment forcooling said air, said secondary system also including a condenserdisposed in contact with the primary element, said secondary systembeing substantially entirely filled with liquid refrigerant to therebyproduce a heat lag between the primary and secondary evaporatingelements-so that the secondary evaporating element operates at leastpart of the time without collecting frost thereon, and means forcontrolling the operating of the primary system in response to changesin temperatures in one of said systems.

8. Refrigerating apparatus comprising a cabinet having an insulated mainfood chamber, a

v refrigerating system comprising a coolingunit in said chamber, saidunit including an enclosure having surfaces exposed for coolingcirculating air in said chamber, and a refrigerated shelf positioned insaid enclosure to divide the interior thereof into a relatively smallfreezing chamber and a relatively large storage chamber, and torefrigerate said enclosure, the exposed surfaces of said enclosure beingso associated with said refrigerated shelf asto cool said main chamberto a refrigerating temperature, solely by the heat absorbing effect ofsaid refrigerated shelf without the formation of ,frost thereon at leastpart of the time while the refrigerated shelf is maintained at a sharpfreezing temperature.

9. Refrigerating apparatus comprising a cabinet having an insulated mainfood chamber, a refrigerating system comprising a cooling unit in saidchamber, said unit including an enclosure having surfaces exposed forcooling circulating air in said chambenand a refrigerated shelfpositioned in said enclosure to divide the interior thereof into twochambers, and means associated with said enclosure for controlling thetemperature of said refrigerated shelf, said means being responsive tothe changes in temperature of a surface ofsaid enclosure to maintain arefrigerating temperature in said main food chamber solely by the heatabsorbing eifect of said refrigerated shelf without the collection offrost on the exterior surfaces of said enclosure at least part of thetime while maintaining the refrigerated shelf at a'sharp freezingtemperature.

10. Refrigerating apparatus including a cooling unit adapted to beinstalled in an insulated food storage chamber comprising a metalliccasing forming a secondary chamber, shelf means within said secondarychamber dividing the same into compartments of unequal height, means forrefrigerating said shelf .means, said secondary chamber having accessmeans for said compartments and closure means for said access means, andmeans influenced bythe temperature of said metallic casing forcontrolling the refrigerating effect of said shelf refrigerating means,said shelf refrigerating means being arranged to refrigerate at leastthe compartment above said shelf to temperatures below freezing and toabsorb heat from said casing to refrigerate the food storage chamberwithout the formation of frost on said casing.

11. Refrigerating apparatus including a cooling unit adapted to beinstalled in an insulated food storage chamber comprising a metalliccasing forming a secondary chamber, refrigerated shelf means within saidcasing for dividing said secondary chamber into a plurality ofcompartments and for refrigerating the same, and means including athermo-bulb contacting a surface of said casing for controlling therefrigerating effect of said shelf means, said casing being arranged torefrigerate said insulated food storage chamber, without the collectionof frost on said casing at least part of the time, solely by therefrigerating effect of said shelf means.

LAWRENCE A. PHIIIPP.

